Television receiver



March 9, 1943. F. OKOLICSANYI TELEVISION RECEIVER Filed April 28, 1939 2Sheets-Sheet 2 anyl',

Fe/"en c Oko/ics' Patented Mar. 9, 1943 UNITE STATES TELEVISION RECEIVERAmerica, New York, N. Y., a

Delaware corporation of Application April 28, 1939, Serial No. 270,672In Great Britain April 29, 1938 18 Claims. (Cl. 1787.5)

The present invention relates to television receiving systems of thetype in which the various elements of the receiving screen are renderedluminous by the action of one or more commutators.

Many forms of such receivers have been proposed. For example it has beenproposed to use a bank of small lamps each of which is in galvanicconnection with one contact of a commutator and which are renderedoperative one after the other by applying to each of them in turn bythe' armature of the commutator a voltage modulated in intensity inaccordance with the received picture signals. Such systems are quiteunsuitable for high definition television owing to V the large number oflamps and commutator contacts which are necessary, and in order toreduce the latter number it has been proposed to use two commutatorsconnected in series with the lamps and the voltage source, onecommutator containing a number of contacts equal to the number ofpicture lines and operating at frame The expense involved in providingthe 200,000

separate lamps, and associated equipment, which would be necessary forhigh definition television, is not the only difliculty to be encounteredin such proposals. Provision must be made for ensuring that thecharacteristic of each lamp is approximately the same, so that a givensignal voltage applied to any lamp will give the same luminous output.This would seem to necessitate the provision of a separate adjustmentfor each lamp, for even if the lamps themselves could 'be manufacturedto the necessary high standard of uniformity, slight differences in thecharacteristics of the conducting paths to the lamps and of otherassociated equipment would seem to be inevitable. The prospect of havingto make 200,000 separate adjustments to such apparatus reduces itspractical value very considerably.

It is an object of the present invention to provide a televisionreceiver of the type described which can be used for high definitionreception,

and in which the cost and complexity of the above mentioned systems isavoided.

According to the present invention there is provided a televisionreceiver comprising a plurality of long evacuated tubes, said tubesbeing arranged vertically in one plane in close proximity to oneanother, a set of elongated electrodes for each tube arranged parallelto the axis thereof, the electrodes comprising a source of electrons, acontrol electrode and an anode. There is also provided an elongatedfluorescent layer for each tube to receive the electrons from the sourceof electrons, and a line frequency commutator in operative connectionwith the control electrodes of the tubes, a picture signal receiver forapplying picture signals to'the armature of the line frequencycommutator, and a frame frequency commutator for controlling all of thetubes simultaneously the incidence of said electrons on the fluorescentlayer from point to point along the length of each tube.

In the case where the source of electrons is thermionic, there arepreferably provided a series of horizontal magnetic controlling memberswhich are energised by the frame frequency commutator in turn. Thearrangement is then made such that in each tube electrons can only reachthe fluorescent layer where the corresponding magnetic member isenergised, the electrons in the remainder of the tube being deflectedaway from the fluorescent layer on to the anode.

The source of electrons may be photo-emissive, and in this case theframe frequency commutator may comprise means such as a mirror drum andco-opcrating optical system for sweeping a horizontal strip of light inthe vertical direction down all the tubes simultaneously. Electrons areemitted in each tube only at the point where the strip of light falls onthe photo-emissive cathode.

A certain storage efiect can be attained by arranging that the controlof the vertical columns persist for a short length of time which mustnot be greater than the line duration period. The electrons can thenreach the picture area at the many crossing point of the simultaneouslycontrolled vertical columns with a single contuted by an electron beam,and optical devices in which it is constituted by a light beam. In thelatter case the usual fixed contacts-are replaced by photoelectriccathodes, which may also serve as the electron controlling meansreferred to above.

By controlling continuous vertical columns with one commutator andcontinuous horizontalrows with the other, instead of controllingindividual elemental areas, the above mentioned difficulties arising outof the use of an individual device for each elemental area are largelyovercome. Thus even in the case of large picture areas of a sizecomparable with that of a full sized cinema screen, the number ofdischarge devices required can be equal to the number of picture lines,and in the case of smaller picture areas, a single device may beemployed.

The invention will now be described by way of example with reference tothe accompanying drawings in which Figs. 1 and 2 illustrate the use ofvertical tubes for building up the picture area;

Fig. 3 shows a mechanical commutator arrangement as an alternative topart of the arrangement of Fig. 1;

Fig. 4 illustrates the use of an optical commutator for the linefrequency scanning;

Fig. 5 is a sectional view of a preferred form of tube:

Fig. 6 is a perspective view of one form of magnetic control for theframe scanning.

Referring to Figs. 1 and 2; each tube 2|, which is preferably of oval orpear-shaped cross section, is provided with a heated cathode 22, a grid23, an anode 24 and a fluorescent screen 25, these electrodes runningthe whole length of the tube.

Each tube has an extension 26 at the lower end which contains the heatedcathode 21, grid 28 and anode 29, the latter being directly connected tothe grid 23 of the main tube. The anodes 24, 29 are connected to asource of positive potential, the latter through a resistance 42, sothat it is at a lower potential than the anode 24.

The line frequency commutator comprises a cathode ray tube 30 having aring of contacts in place of the normal fluorescent screen. The beam ofthis tube is deflected in a circular fashion over this ring of contactsby means of line frequency synchronizing impulses applied to thedeflecting coils 32, 33. The picture signals from the receiver l8 areapplied to the grid 34 to modulate the intensity of the beam. Each ofthe contacts 3| is connected to a grid 28 and to earth through a leakageresistance 35. As the beam of the cathode ray tube strikes each contact3| in turn, negative impulses carrying in amplitude in accordance withthe received picture signals will be applied in turn to the grids 28 oftriode extensions 26, and consequently, amplified positive impulses willbe applied in turn to the grids 23 of the main tubes 2|, thus allowingthe electrons from the cathode 22 to pass and reach the anode 24. Theleakage time of the negative charges applied to the grids 28 will dependupon the time constant. of the circuit formed by the resistance 35 andthe shunt capacity between the grid 28 and earth. This time constant canbe chosen so that the negative charges persist for a time whichapproaches but does not exceed the duration time of a picture line, sothat a storage effect can be obtained.

vIn some cases the triode extension 26 to each tube can be dispensedwith, and the contacts 3| connected directly to the grids 23 of the maintubes. In this case, however, the contacts must be coated with asecondary electron emitting layer having a very high ratio of secondaryelectrons emitted to primary electrons incident thereon, so thatpositive charges are set up on the contacts in proportion to the numberof secondary electrons ejected therefrom. The normal collectingelectrode for collecting the secondary electrons must be provided.

The frame frequency commutator comprises a second cathode ray tube 36with contacts 31 and deflecting coils 38, 39 energized by the receivedframe synchronizing impulses to deflect the beam over the contacts. Eachcontact is connected to a wire 40 running across the front of the tubes2| at right angles to their axes. The opposite ends of all the wires 40are connected to earth, so that as the beam of the cathode ray tube 36strikes one of the contacts 31, a current will flow through the wire 40connected to that contact. This current will produce a localizedmagnetic field having a component parallel to the axes of the tubes 2|,and this localized field will act on the electron stream in that portionof each tube which lies opposite the wire to defiect it from the anode24 on to the fluorescent screen 25. Thus as a current flows in each ofthe wires 40 in turn, this localized field will move down the tubes,thus eifecting the frame scanning. In actual practice the number ofwires 40 can be much greater than the required number of picture lines,and by using a correspondingly greater number of contacts in conjunctionwith a cathode ray beam of such a cross section that it covers a groupof these contacts, the magnetic field can be given a substantiallycontinuous movement.

In front of the wires is placed a suitable diffusing screen 4| arrangedat such a distance from the tubes 2| that the light emitted from thefluorescent material is slightly spread by the screen to give acontinuous illumination.

Instead of cathode ray commutators, mechanical commutators can be used,in the manner shown in Fig. 3. Potentials can be applied in turn to thegrids 26 through the armature ll of the commutator l2 from the signalreceiver l8, these potentials being modulated in amplitude in accordancewith the received picture signals. Also, positive potentials can beapplied in turn to the wires 40 through the armature 20 of thecommutator l4 to cause currents to flow therein. The armature ll rotatesat the line scanning frequency and the armature 20 at the frame scanningfrequency, the rotation being controlled by the received line and framesynchronising impulses respectively.

The line frequency commutation can also be performed by means of anoptical commutator. This is illustrated in Fig. 4, in which the tube 2|is modified by omitting the grid 28, and replacing the heated cathode 21by a photo electric cathode 43. A beam of light from the source 44 isswept over the cathode 43 in turn by means of a mirror drum 45, whichrotates at the line scanning frequency. The intensity of the light beamis modulated in accordance with the received picture signals by means ofany suitable form of light modulator 46, such as a. Kerr cell orsupersonic wave cell. The anode 29 incorporates a secondary electronemitting layer, so that as each photo-cathode 43 is illuminated, theelectrons emitted will eject a proportionately greater number ofsecondary electrons from the anode 29, which are collected by the usualcollecting electrode (not shown), and which leave the anode 29, andconsequently the grid 23, with a proportionate positive charge. Theremainder of the apparatus is similar to that shown in Figs. 1 and 2.Instead of modulating the lightbeam in accordance with the picturesignals, an unmodulated light beam can be used, in which case the grid28 is retained, and the picture signals are applied to all the grids 28simultaneously.

A sectional view of one form of the tubes H is shown in Fig. 5 in orderto show more clearly the constructional details. prises a long nickelcylinder coated with an electron emitting material and having a heaterwire coated with porcelain running through it. The

- cylindrical grid 23 is supported by mica spacing pieces 41 situated atintervals along the length of the tube, which also support focussingelectrodes 48. The anode 24 and fluorescent screen 25 are carried by thewall of the tube.

In Fig. 6 is shown an alternative form of the magnetic deflecting meansfor effecting the frame scanning. Each magnetic circuit for energizing apicture line comprises an iron core in the form of a channel sectionmember 50, the end portion of two of these members being shown in thefigure. The opposite sides 5|, 52 of this member are provided withelongated apertures 53 through which the tubes 2| pass, two of thesetubesbeing shown. The base of each member is surrounded by an energizingcoil 54 wound in such a sense that the sides 5|, 52 form the oppositepoles of a magnetic system, the flux between these poles runningparallel to the axis of the tubes to produce the necessary deflection ofthe electron streams in the tubes 2|. Each of the coils 54 is connectedto one of the contacts of the frame scanning commutator, so that thecoils are energized in turn.

Storage of the received signals can be effected in all cases bycontrolling the leakage time of the charges which control the linescanning. Alternatively it can be effected by providing no permanentleakage path, but by periodically connecting the line scanningelectrodes to earth or to a source of negative potential atpredetermined time intervals after each positive charge has beenapplied. This can be done by providing the line frequency commutatorwith a second armature which followsthe first and which makes therequired connection after the required time interval has elapsed. Thesame method may be applied to the frame frequency commutator in order toensure that the frame scanning control is cut off at the correct moment,if this proves to be necessary.

Subject-'matter disclosed but not claimed herein is claimed inapplication Serial No. 472,240,

The cathode 22 com-- filed January 13, 1943, for Television receivers,

which is a division of this case.

I claim as my invention;

1. A television receiver comprising a plurality of long evacuated tubes,said tubes being arranged vertically in one plane in close proximity toone another, a set of elongated electrodes for each tube arrangedparallel to the axis thereof, said electrodes comprising a source ofelectrons, a control electrode and an anode, an elongated fluorescentlayer for each tube adapted to receive such electrons from said sourcethat pass said control electrode and anode, a plurality of magneticcontrolling members arranged horizontally and externally of said tubes,a line frequency commutator in operative connection with the controlelectrodes of said tubes, a frame frequency commutator in operativeconnection with said magnetic controlling members, a picture signalreceiver in electrical connection with the armature of said linefrequency commutator and asource of electrical current in electricalconnection wlth'the armature of said frame frequency commutator.

2. A television receiver according to claim 1 wherein said magneticcontrolling members comprise a plurality of horizontal wires connectedto contacts in said frame frequency commutator.

3. A television receiver according to claim 1 wherein said magneticcontrolling members comprise a plurality of horizontal magnetic coreshaving pole pieces which extend horizontally over the whole of thepicture area and are separated vertically by an amount not exceeding thewidth of a picture line, and an energizing winding for each of saidcores, said windings being connected f to contacts in said framefrequency commutator.

4. A television receiver comprising a plurality of long evacuated tubes,said tubes being arranged vertically in one plane in close proximity toone another, a set of.elongated electrodes for each tube arrangedparallel to the axis thereof, said electrodes comprising a source ofelectrons, a control electrode and an anode. an elongated fluorescentlayer for each tube adapt- .ed to receive such electrons from saidsource that pass said control electrode and anode, an evacuatedextension for each tube, said extension being provided with a cathode,control grid and anode, said anode being in electrical connection withthe control electrode of said tube, a plurality of magnetic controllingmembers arranged horizontally and externally of said tubes, a linefrequency commutator having contacts connect- 'ed to the control gridsof said extensions, a frame frequency commutator in operative con--nection with said magnetic controlling members, a picture signalreceiver in electrical connection with the armature of said linefrequency commutator and a source of electrical current in electricalconnection with the armature of said frame frequency commutator.

5. A receiver according to claim 4, wherein said line frequencycommutator comprises a cathode ray tube having said contacts within theenvelope thereof, a source of cathode rays for said tube, and means fordeflecting said cathode ray over said contacts.

6. A television receiver comprising a plurality of long evacuated tubes,said tubes being arranged vertically in one plane in close proximity toone another, a set of elongated electrodes for each tube arrangedparallel to the axis thereof, said electrodes comprising a source ofelectrons, a control electrode and an anode, an elongated fluorescentlayer for each tube adapted to receive such electrons from said sourcethat pass said control electrode and anode, an evacuated extension foreach tube, said extension being provided with a photo-electric cathode.and an frequency. a frame frequency commutator in operative connectionwith said magnetic controlling members and a source of electricalcurrent in electrical connection with the armature of said framefrequency commutator.

7. A television receiver comprising a plurality of. long evacuatedtubes, said tubes being arranged vertically in one plane in closeproximity to one another, a set of elongated electrodes for each tubearranged parallel to the axis thereof, said electrodes comprising asource of electrons, a control electrode and an anode, an elongatedfluorescent layer for each tube adapted to receive such electrons fromsaid-source that pass said control electrode and anode, an evacuatedextension for each tube, said extension being provided with aphoto-electric cathode, a control grid and an anode, said anode beingcapable of a high secondary electron emission and being in electricalconnection with the control electrode of said tube, a plurality ofmagnetic controlling members arranged horizontally and externally ofsaid tubes, means for developing a light beam, means for periodicallysweeping said light beam over said photo-electric cathodes at the linescanning frequency, a picture signal receiver electrically connected tothe control grid of said extensions, a frame frequency commutator inoperative connection with said magnetic controlling members and a sourceof electrical current in electrical connection with the armature of saidframe frequency commutator.

8. A television receiver comprising a plurality of long evacuated tubes,said tubes being arranged vertically in one plane in close proximity toone another, a set of elongated electrodes for each tube arrangedparallel to the .axis thereof, said electrodes comprising a source ofelectrons, a control electrode and an anode, an elongated fluorescentlayer for each tube adapted to receive such electrons from said sourcethat pass said control electrode and anode, an evacuated extension foreach tube, said extension being provided with a cathode, control rid andanode, said anode being in electrical connection with the controlelectrode of said tube, a plurality of magnetic controlling membersarranged horizontally and externally of said tubes, a cathode ray tubeconstituting a line frequency commutator, a source of cathode rays forsaid tube, a series of commutator contacts and means for deflecting saidcathode rays over said contacts, a frame frequency commutator inoperative connection with said magnetic controlling members, a picturesignal receiver in electrical connection with the cathode ray tube ofsaid line frequency commutator and a source of electrical current inelectrical connection with the armature of said frame frequencycommutator.

9. A television receiver comprising a plurality of long evacuated tubesarranged side by side in one plane, and having their length extending inthe frame scanning direction, and within each tube and extending alongthe length thereof, a cathode, a control electrode and a fluorescentscreen; a line frequency commutator comprising a plurality ofphoto-electric cathodes, an anode associated with ,ach cathode toreceive electrons therefrom, means for sweeping a light beam over eachcathode in turn to cause the emission of electrons therefrom and toproduce a voltage change on said anodes, means for controlling saidvoltage changes in accordance with received television signals; andmeans for applying said voltage changes to said control electrodes,where- 'by each control electrode receives in turn a, voltage such as topermit the passage of electrons to said fluorescent screen to an extentdependent upon said received television signals, magnetic controllingmeans for permitting the passage of electrons to said fluorescent screenin a part only, at any instant, of the length of said tubes, and a framefrequency commutator for energising said controlling means.

10. A television receiver comprising a plurality of long evacuated tubesarranged side by side in one plane, and having their length extending inthe frame scanning direction, and within each tube and extending alongthe length thereof, a cathode, a control electrode and a fluorescentscreen; a line frequency commutator for applying to each controlelectrode in turn a voltage such as to permit the passage of electronsto said fluorescent screen to an extent dependent upon receivedtelevision signals; a plurality of magnetic controlling members situatedat right angles to and externally of said tubes for controlling thepassage of electrons to said fluorescent screen in different portions ofall the tubes, and a frame commutator for energising said magneticcontrolling members in turn.

11. A television receiver according to claim 10 wherein said magneticcontrolling members com prise a plurality of wires connected to saidframe frequency commutator so as to be energised in turn thereby.

12. A television receiver according to claim 10 wherein said magneticcontrolling members comprise a plurality of magnetic cores having polepieces which extend over the whole of the picture area in the framescanning direction, and are separated in the line scanning direction byan amount not exceeding the width of a picture line, and an energisingwinding for each of said cores, said windings being connected to saidframe frequency commutator so as to be energised in turn thereby.

13. A television receiver comprising a plurality of long evacuated tubesarranged side by side in one plane, and having their length extending inthe frame scanning direction, and within each tube and extending alongthe length thereof, a cathode, a control electrode and a fluorescentscreen; an extension for each tube, and within said extension an anodeconnected to said control electrode and a cathode; line commutatingmeans for permitting the passage of electrons from said cathode to saidanode in each tube in turn and control means for rendering the extent ofsaid passage of electrons dependent upon received television signals,whereby each control electrode receives in turn a voltage such as topermit the passage of electrons to said fluorescent screen to an extentdependent upon said received signals; magnetic controlling means forpermitting the passage of electrons to said fluorescent screen in partonly, at any instant, of the length of said tubes, and a frame frequencycommutator for energizing said controlling means.

14. A television receiver according to claim 13 wherein the cathode ineach of said extensions is photo-electric and the anode in each of saidextensions is highly emissive of secondary electrons; and said linecommutating means comprise means for sweeping a light beam over saidphoto-electric cathodes in turn and said controlling means comprisemeans for modulating said light beam with said received televisionsignals.

15. A television receiver according to claim 13 wherein the cathode ineach of said extensions is photo-electric and the anode in each of saidextensions is highly emissive of secondary electrons; wherein said linecommutating means comprise means for sweeping a light beam over saidphotoelectric cathodes in turn, to cause an emission of electrons fromeach in turn; and wherein said controlling means comprise a controlelectrode in each extension and means for feeding said receivedtelevision signals to all said control electrodes simultaneously.

16. A television receiver comprising a plurality of long evacuatedtubes, said tubes being arranged vertically in one plane in closeproximity to one another, a set of elongated electrodes for each tubearranged parallel to the axis thereof, said electrodes comprising asource of electrons, a control electrode and an anode, an elongatedfluorescent layer for each tube for receiving such electrons from saidsource, a line frequency commutator in operative connection with thecontrol electrodes of said tubes, a picture signal receiver for applyingpicture signals to the armature of said line frequency commutator,magnetic controlling means for controlling in all said tubessimultaneously the incidence of electrons on said fluorescent layer frompoint to point along the length of each tube, and a frame frequency commutator for energising said control means, Where in said control meanscomprise a plurality of horizontally arranged magnetic controllingmembers placed externally of said tubes and said frame frequencycommutator is adapted to energise said members in turn.

17. A television receiver comprising a plurality of long evacuated tubesarranged side by side in one plane, and having their length extending inthe frame scanning direction, and within each Y tube and extending alongthe length thereof, a

cathode, a control electrode and a fluorescent screen; an extension foreach tube, and within said extension an anode connected to said controlelectrode and a photo-electric cathode; an optical line commutatorcomprising means for sweeping a light beam at line frequency over saidphotoelectric cathodes in turn to release electrons therefrom and togenerate charges on said anodes of said extensions; a picture signalreceiver and electrical means in connection therewith for controllingthe number of electrons reaching said anodes of said extensions inaccordance with received picture signals, whereby each control electrodeof said tubes receives in turn a voltage such as to permit the passageof electrons to said fluorescent screen to an extent dependent upon saidreceived signals; magnetic controlling means for permitting the passageof electrons to said fluorescent screen in part only, at any instant, ofthe length of said tubes, and a frame frequency commutator forenergising said controlling means.

18. A television receiver according to claim 13 wherein the cathode ineach of said extensions is thermo-emissive, and said line commutatingmeans comprise a cathode ray tube having a plurality of contactsarranged to be commutated by the cathode ray beam; wherein there isprovided a control grid within each of said extensions, each controlgrid being connected to one of said contacts; and wherein saidcontrolling means comprise 'means for modulating said cathode ray beamin accordance with said received television signals.

FERENC OKOLICSANYI.

